Am I able to do a give away for an origin key?

No giveaways for anything that isn't Steam redeemable.

You're not allowed to make a giveaway for any platform besides Steam.

You cannot give it away as a Steam Gifts giveaway. You can give it away here on the forums as a key drop, puzzle or something, but if it's a giveaway, it has to be Steam redeemable, hence why the site is not called Origin Gifts.

Please review the following guidelines and keep them in mind when participating in the community.
http://www.steamgifts.com/about/guidelines

Giveaways

Creating

• All giveaways should be for Steam redeemable gifts or Steam redeemable keys.

You may however use the forums to create a puzzle or random member giveaway of an Origin key.
Some here use - http://www.itstoohard.com/create
Or simply just drop the key in plain text and run away.

Free Red Alert uprising key then ! FBQY-4W3Z-HZ2Q-UQ7Z-4LK9 bewm

ya people are quick and lack thanks =P

You can, just do it in the forums as opposed to officially.

What a deal !!